Former MLB player Jeremy Giambi died by a self-inflicted gunshot wound ... according to the medical examiner in Los Angeles.
He was only 47 years old.
As we previously reported, sources told us it was evident the former 7-year Major League Baseball vet took his own life earlier this week at his parents' home in the L.A. area.
We're told a family member found Jeremy around 11:40 AM on Wednesday ... and immediately dialed 911. Rescuers responded, but sadly, there was nothing they could do to help Giambi.
Jeremy played from 1998 to 2003 ... for the Royals, Athletics, Phillies, and Red Sox. He had a career batting average of .263, hit 52 home runs, and batted in 209 runs throughout his career.
His best season came in 2002, when he played in 124 games and hit 20 homers.
The Athletics issued a statement on Jeremy's death, saying ... "We are heartbroken to learn of the passing of a member of our Green and Gold family, Jeremy Giambi. We offer our condolences to Jeanne, Jason, and his family and friends."
Jeremy is the younger brother of former AL MVP Jason Giambi.